[unreadable] Recent findings have suggested that N-acetylcysteine (NAC) substantially reduces cocaine-primed drug-seeking behavior in formerly cocaine-dependent rats. The present proposal involves two components that simultaneously examine the impact of NAC within cocaine-dependent humans and rodents. The first component is an inpatient study that involves two 3-day hospital stays in which subjects receive either 4 doses of NAC or placebo. Subjects will undergo a cue reactivity procedure during their stay. It is predicted that cocaine-dependent individuals will show greater reactivity to cocaine cues during placebo relative to controls. It is predicted that NAC will reduce this cue reactivity in cocaine-dependent individuals. The second component examines the extent to which NAC reduces cocaine-seeking behavior in rodents and is designed to closely emulate the experimental conditions of clinical trials involving humans. Rats will receive access to cocaine via lever press. They will then be withdrawn from cocaine administration for an extended time, then reintroduced to free access to either saline or cocaine. Half will be treated with NAC prior to the free access period. It is proposed that NAC will reduce cocaine-seeking behavior. [unreadable] [unreadable] [unreadable] [unreadable]